DRietz

Hey there, mechanics-who-outrank-me-in-experience-with-this-sort-of-thing. I recently acquired a Nuovo Record Campagnolo headset for my Mercian, and was seating the cups so I could press them in.

While seating the lower cup, I pushed a bit harder and the cup went into the headtube. Same with the top cup. They were pretty easy to get in, but not that easy. They turn in the headtube with some resistance.

Is this dangerous? What are my options?

fietsbob

should be fine , to get it tight , Loc Tite Red is what is used for seating sealed bearings ,

and so as more gap filling , than the blue thread loc. you could get a few ML of that a tube, at auto parts store..

cny-bikeman

Dangerous is the wrong word, but that is not good. The cups will rock under load, wear prematurely and possibly even make the head tube worse than it is now after a while. I would get an accurate set of vernier calipers to measure the head tube and cups. Refer to the Park site for more info. https://www.parktool.com/repair/readhowto.asp?id=127

Sixty Fiver

Blue loctite is your friend... should make for a more secure fit.

reptilezs

i would use a retaining compound

duckforcover

a. nobody knows everything
b. If they can be turned in the headtube, that is a bad sign.
c. Chances are, you will go through several headset re-adjustments initially.
d. Depending on how hard you ride, it may last a day or a year before play develops especially under front braking.
e. The chances of it falling apart and doing some damage are slim to none.
f. Eventually, you might end up thinking about it so much that you can't enjoy your rides.
.
.
.
z. If it were my bike, I'd run it.

cny-bikeman

Again, follow the Park instructions to determine if Loctite/retaining compound will work or if you are not able to use that headset.

BCRider

For this application I'd suggest some blue or red loctite. I certainly would not leave it loose like that. You WANT them to be tight in the frame. I'd probably go with blue and check it occasionally by trying to twist the exposed rim of the cups. If I find they are loose and able to turn by hand pressure than I'd redo the locking sealant with red. I strongly suspect that the yellow stud and bearing mount is a little above and beyond though.

AEO

what might be your case, is that you're using a JIS headset, or JIS cups in an ISO frame.

JIS headset cup outer diameter is 30.0mm
ISO heaset cup outer diameter is 30.2mm

or someone used ISO cups in a JIS frame, and spread out the crown by 0.2mm.

it's no big deal as there are plenty of easy fixes that have already been mentioned.

DRietz

So, Loctite 609 retaining compound. Sounds like it'll work. With a caliper, the cups are within .5mm of the head tube diameter, so that means that I can use this (that's what Park claims).

How do I go about doing it? Use the retaining compound like I would grease on a normal headset and smear it on the parts of the cups inserted into the head tube?

reptilezs

a retaining compound can usually fill gaps as big as .005 inches or .127mm. are you measuring with a good caliper/using good technique?

cny-bikeman

That has to be a typo or your measurement is inaccurate. If the race is .5mm smaller than the head tube ID it would fall out, if larger there's no way it would go in. The OD of the race has to be at least .10 mm larger than the head tube ID for even retaining compound or Loctite to work. Even .05mm larger than the head tube is unacceptable according to the Park criteria.

If you read further down on the Park page there is also a full chart of headset sizing specs.

Servo888

This! I had the same issue, so I simply cleaned the cups, the headtube (you must remove all the grease) and then simply smothered on the blue loctite to the inside of the frame, and the outside of the cups. When I sold the frame, the cups came out just fine.

DRietz

Yes, it was a typo. It was late at night. I forgot to add the leading zeros. M'bad...

But what about my question? Just like the grease then?

cny-bikeman

Yes, just apply it after thoroughly cleaning. But we still have a problem. Leading zeros? Does that means .005 or .05? Either one is smaller than the standard on the Park site. No harm in trying the fix. If it works, great - but be aware it may not hold.

BCRider

The 609 product is a more high strength "stud and bearing" locking compound. It's the sort of stuff that would be much, much harder to remove the headset cups later without resorting to heating to over 250C. That's more than hot enough to scorch or lift the paint off the metal of the headset. You sure you don't want to go with the softer holding blue or red? The blue for sure and likely the red would allow for eventual removal with our usual bicycle methods and tools. But the 609 sure looks from the application chart to be almost as permanent as welding the cups into the frame.

Lookie here....
https://tds.loctite.com/tds5/docs/609-EN.pdf

I don't know about the 609 as I haven't used THAT locking product but the thread lockers are thin enough that I'd wipe a thin coat onto the inside of the frame head tube and around the cup and then twist and press them together. They are thin enough that it would be more like applying a coat of oil than smearing on grease. Leave for a few hours for the stuff to cure hard enough to continue putting the bike together and at least 24 hours before riding.

JohnDThompson 

OP states he was able to hand fit Campagnolo cups into the head tube. AFAIK, Campy never made JIS headset parts.

I wonder if this is a lugless (fillet brazed or TIG welded) frame? These have a tendency to flare the head tube if the bike is ridden with a poorly adjusted headset for long enough, unless the builder used reinforcing rings at the ends of the head tube.

DRietz

Unfortunately, it's just an over-reemed lugged Mercian. I'll pick up some of the retaining compound tomorrow and hopefully that'll work out.

...or maybe some blue thread locker. The red stuff is nasty and incredibly hard to get apart.